1. Field of the Invention
The present invention pertains to a brush holder assembly as used in small electric motors or generators. The assembly includes a brush holder, a brush, and a brush spring for urging the brush in a direction to expel it from an open end of the brush holder. When the assembly is complete, the brush spring will hold the brush against the commutator.
2. Description of the Prior Art
Many types of brush holder assemblies have been devised for a variety of specific applications. Some designs are directed principally to economy while others are directed to ease of assembly. Other design features include: maintenance of proper contact pressures between brush and commutator; means for indicating that a brush should be replaced; improvement of the electrical conduction from the brush to another point; and other design criteria.
It is generally desirable to provide a means to prevent the total wearing away of the brush and particularly to prevent the brush spring, which urges the brush towards the commutator, from ever coming in contact with the commutator. In the past, it has been customary to satisfy this design criteria by the use of a pigtail type connection between the brush and some reference point. That is, a pigtail of flexible stranded wire is securely coupled to the interior end of the brush and the other end of the pigtail is secured to the interior of the brush holder with such a length between the two ends of the pigtail that the forward motion of the brush is limited and so that, therefore, neither the brush spring nor the pigtail may ever come in contact with the motor commutator.